淅川盆地上白垩统蜥脚类幼年个体新材料

描述湖北郧县淅川盆地晚白垩世地层中产出的蜥脚类恐龙化石。标本保存于上白垩统马家村组中段灰绿色含钙泥质粉砂岩中,材料包括牙齿、脊椎和肢骨化石等。从愈合特征(如分离的椎体和椎弓)分析,这些化石至少由2个未成年个体组成。这些化石体现出的特征组合,如股骨近端外侧突出,近端外缘向内侧倾斜,荐前椎气腔构造发育,以及牙齿呈细长的棒状,表明湖北郧县马家村组地层发现的蜥脚类可归入巨龙形类中的多孔椎龙类或者更进步的类群。新材料的发现对于进一步了解中国乃至东亚地区白垩纪晚期的蜥脚类恐龙分布和演化具有一定的意义。     

中国河南晚白垩世地层一枚可能属于重爪龙亚科(兽脚亚目:棘龙科)的牙齿化石(英文)

中国河南晚白垩世中段地层马家村组发现了一枚大型兽脚龙类牙齿。该牙牙体长,呈圆锥状,横断面卵圆形,沿长轴微向后缘弯曲,前后缘均有大量锯齿状突起,这些特征显示其很可能是重爪龙类牙齿。这可能代表了重爪龙类在亚洲地区的首次发现,也是该类恐龙在晚白垩世地层中的首现,由此表明重爪龙类在时间和地域分布上较之前研究观点更为广泛。综合棘龙科的化石形态学以及推知的生态学证据看,较之其他兽脚类,棘龙类化石记录很少,很可能意味该类动物数量确实稀少,造成这种现象的原因可能是其过分特化的身体形态。     

辽西热河群的恐龙化石

恐龙是地球历史上最为成功的一类爬行动物 ,它的起源、演化和绝灭一直是古生物研究领域的热点问题。我国恐龙化石的发现和研究在世界上占有重要的地位。从恐龙化石的产出情况来看 ,中国是一个当之无愧的恐龙大国 :恐龙化石分布地理范围广泛 ,西起新疆 ,东到辽宁 ,南起广东 ,北到内蒙 ;恐龙化石分布层位齐全 ,从恐龙开始初步繁盛的早侏罗世地层 ,到世界上恐龙化石非常贫乏的中侏罗世地层 ,从恐龙第一次大繁盛的晚侏罗世地层到恐龙走向绝灭的晚白垩世地层 ,恐龙属种都非常丰富 ,从原蜥脚类恐龙到体形巨大的蜥脚类恐龙 ,从凶猛的兽脚类恐龙到植…     

禄丰发现新的恐龙化石

我国著名的恐龙之乡———禄丰 ,最近在川街乡发现了一个新的恐龙化石墓地。恐龙化石产于中—上侏罗统的上禄丰组的底部的一套紫红色的砂质泥岩中。在已发掘的４００平方米范围内初步统计出露恐龙化石有巨型的蜥脚类恐龙骨架８具 ,其中有一具近于完整 ,长约１９米 ,肉食性兽脚类恐龙骨架一具 ,还有众多的蛇颈龟化石。埋藏学分析这些动物在死亡后遭到过搬运 ,但搬动的距离不远 ,化石保存较完好也较集中。经鉴定 ,蜥脚类恐龙应归于马门溪龙科 ,兽脚类恐龙相似四川上沙溪庙组产出的永川龙 ,它们生存的时代也应相近 ,距今一亿五千万年前中侏罗世…     

中加古生物学家在新疆发现恐龙

[本刊讯]中国-加拿大联合考察队最近在我国新疆准噶尔盆地将军戈壁发现一批恐龙化石,其中包括巨型蜥脚类、兽脚类等,除外还有一些鳄类化石。上述化石均产自侏罗纪地层中(距今约1.50亿年)。考察队     

江苏下白垩统孟疃组的恐龙足迹群及蜥脚类足迹形态的多样性(英文)北大核心

中国江苏省东海县南古寨孟疃组发现了数种恐龙足迹,包括兽脚类足迹和蜥脚类足迹。这些足迹出现在同一层位的四个相邻的足迹化石点。这些足迹化石点至少保存了三种不同形态的兽脚类足迹和未成年—成年的蜥脚类足迹。南古寨三号足迹化石点的兽脚类足迹和蜥脚类足迹出现了"回填"现象,这是在足迹所附带的沉积物与基底地面相互作用下,产生的流体和塑性行为下形成的。     

江苏下白垩统孟疃组的恐龙足迹群及蜥脚类足迹形态的多样性(英文)

中国江苏省东海县南古寨孟疃组发现了数种恐龙足迹,包括兽脚类足迹和蜥脚类足迹。这些足迹出现在同一层位的四个相邻的足迹化石点。这些足迹化石点至少保存了三种不同形态的兽脚类足迹和未成年—成年的蜥脚类足迹。南古寨三号足迹化石点的兽脚类足迹和蜥脚类足迹出现了"回填"现象,这是在足迹所附带的沉积物与基底地面相互作用下,产生的流体和塑性行为下形成的。     

内蒙古查布地区下白垩统巨齿龙足印化石

内蒙古鄂尔多斯市鄂托克旗查布地区下白垩统中产有大量的蜥脚类和兽脚类恐龙足迹及鸟类足迹化石,作者对这个地区的足迹化石进行全面普查,发现许多新暴露出来的恐龙足迹化石,包括兽脚类恐龙足迹一新属新种Chapuslockleyiichnogen.etichnosp.nov.属于巨齿龙类(megalosaurid)所留。与兽脚类足迹保存在一起的蜥脚类足迹Brontopodusbirdi分布凌乱,反映了造迹恐龙搏斗的场面。通过测量连续的兽脚类足迹计算,Chapuslockleyi的造迹恐龙的行走速度为4.33km/h。通过足迹化石还识别出造迹恐龙的病态特征。     

四川省自贡市发现大批恐龙化石

在批林批孔运动高潮中,根据自贡市建筑公司木材加工厂职工在进行基本建设工程时发现的化石线索,重庆市博物馆在自贡市盐业历史博物馆和有关单位的大力协助下,从1974年3月开始,进行了三个月的发掘工作,共获得106箱化石。此批化石系以蜥脚类恐龙为主,兼有兽脚类和剑龙的部分化石。蜥脚类有二具长约15米左右较完整的个体。剑龙有部分牙和牙床、椎骨、肢骨、骨板和尾刺等,此外还发现少见的肉食性恐龙的幼体,在这批化石中还有上述几类恐龙的牙齿300多颗,材料比较丰富。为了及时修复、整理、研究这批重要化石材料,重庆市博物馆与中国科学院古脊椎动物与古人     

湖南株洲晚白垩世恐龙化石的初步研究

我国南方上白垩统产丰富的恐龙蛋化石,但发现的恐龙骨骼化石的种类和数量相对较少。本文对湖南株洲天元区新发现的恐龙化石进行详细研究。初步分析结果表明该化石点恐龙种类丰富,可能包括至少两种蜥脚类、三种兽脚类和一种鸭嘴龙类。其中部分蜥脚类材料可能归属于梁龙超科,填补了该类群在东亚上白垩统的空白记录;一个蜥脚类坐骨则显示泰坦巨龙类的典型特征。兽脚类材料可能来自于小型的虚骨龙类、暴龙科和鲨齿龙科。前两者为晚白垩世的常见类群,而鲨齿龙科的化石记录在上白垩统非常少见。本文为鲨齿龙科可能在东亚一直延伸至晚白垩世提供了新的证据。该地区多门类恐龙化石的发现表明我国南方恐龙的种类可能比我们想象的要丰富得多,而且可能是梁龙类和鲨齿龙类的最后栖息地。株洲恐龙动物群的发现对于了解亚洲特别是中国恐龙的生物地理区系的分布具有重要意义。     

New record of a sauropod in the Jurassic–Cretaceous transition of the Iberian Peninsular (Spain): palaeobiogeographical implications

In recent decades a unique association of basal neosauropod and turiasaur sauropods has been described from the Jurassic–Cretaceous transition of Spain. In this context, a sauropod femur from the Tithonian–Berriasian is studied for the first time. The femur in question is an isolated specimen, recovered from the Tera Group in Tera (Soria). It displays a unique mosaic of derived characters as yet undescribed in femora of the Upper Jurassic and Lower Cretaceous of Spain. A prominent lateral bulge, high eccentricity, and a lateromedially flattened proximal end link the femur from Tera with Titanosauriformes. Moreover, it presents a significant distal projection of the tibial condyle, a character observed in Asiatic Titanosauriformes of the Lower Cretaceous. The femur from Tera adds a fifth sauropod taxon to the Tithonian–Berriasian of Spain, and, for the first time, a representative of Titanosauriformes.     

On the Occlusal Fit of Tribosphenic Molars: Are We Underestimating Species Diversity in the Mesozoic?

The complex occlusal fits between tribosphenic teeth are a rich source of information for taxonomic, phylogenetic, and evolutionary analysis. The degree of fit between upper and lower cheek teeth has been used to refer specimens to species-level taxa, but statistical data on occlusal fit in relation to taxonomic identity have been lacking. We used landmarks on upper and lower first molars of 20 bat populations representing 16 species to assess the degree of occlusal fit (1) between teeth from the same individual; (2) between teeth from different individuals belonging to the same populations; and (3) between teeth belonging to different populations. We found that the fit of teeth belonging to different populations was significantly worse than between those of the same population and that the degree of misfit increased linearly with time since common ancestry, albeit with substantial variance. We used our comparisons to assess the species-level diversity within Batodon, the smallest known placental mammal from the Cretaceous. Our data suggest, with caveats, that instead of belonging to a single species, the specimens assigned to Batodon represent at least two species as different as those belonging to different genera or families of living bats.     

The radula of the Late Cretaceous scaphitid ammonite Rhaeboceras halli (Meek and Hayden, 1856)

Abstract: Radular teeth occur between the jaws in two specimens of the Late Cretaceous scaphitid ammonite Rhaeboceras halli (Meek and Hayden, 1856) from the Western Interior of the United States. The detailed morphology of the teeth has been revealed by propagation phase contrast X‐ray synchrotron microtomography. Each row of the radula of R. halli consists of a total of seven teeth (a central rachidian, two pairs of lateral and one pair of marginal teeth), as in other known ammonoid radulae, although the central tooth could not be confirmed in the specimens examined. The lateral teeth are multicuspid and robust, and the marginal teeth are long (4.6 mm) and slender. In overall morphology, the heterodont and ctenoglossan radula of R. halli is similar that of Jurassic and Cretaceous ammonites with the same aptychus‐type lower jaw, that is, the Aptychophora. This discovery reveals the range of variation in radular morphology, which could be related to ecological or phylogenetic factors. It also invalidates the hypothesis that the hook‐like structures in R. halli previously described are radular elements.     

Body size evolution in Titanosauriformes (Sauropoda,Macronaria)

Titanosauriformes is a conspicuous and diverse group of sauropod dinosaurs that inhabited almost all land masses during Cretaceous times. Besides the diversity of forms, the clade comprises one of the largest land animals found so far, Argentinosaurus, as well as some of the smallest sauropods known to date, Europasaurus and Magyarosaurus. They are therefore good candidates for studies on body size trends such as the Cope's rule, the tendency towards an increase in body size in an evolutionary lineage. We used statistical methods to assess body size changes under both phylogenetic and nonphylogenetic approaches to identify body size trends in Titanosauriformes. Femoral lengths were collected (or estimated from humeral length) from 46 titanosauriform species and used as a proxy for body size. Our findings show that there is no increase or decrease in titanosauriform body size with age along the Cretaceous and that negative changes in body size are more common than positive ones (although not statistically significant) for most of the titanosauriform subclades (e.g. Saltasaridae, Lithostrotia, Titanosauria and Somphospondyli). Therefore, Cope's rule is not supported in titanosauriform evolution. Finally, we also found a trend towards a decrease of titanosauriform mean body size coupled with an increase in body size standard deviation, both supporting an increase in body size variation towards the end of Cretaceous.     

Juvenile and adult teeth of the titanosaurian dinosaur Lirainosaurus (Sauropoda) from the Late Cretaceous of Iberia

A large sample of more than 100 teeth of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous Laño quarry (Northern Spain) has been studied. Most of the teeth are small (crown height less than 13 mm), cylindrical, with parallel edges and smooth enamel; a few larger teeth are tapered and have more ornamented enamel. These differences are regarded here as ontogenetic changes, the small teeth being interpreted as those of juveniles and the large ones as those of subadult or adult individuals. The juvenile teeth also present some differences in the apex of the crown: some of them have a tapered tip, and others have apical and/or mesial/distal facets. The first are probably unerupted or non-functional teeth, while the ones with wear facets are functional teeth. This is the first time a change in the microwear structures of the apical wear facets between juvenile and adult teeth is observed in a titanosaurian taxon. Moreover, this let us to hypothesize a switch in the diet and food processing between the juvenile and adult individuals of Lirainosaurus. Finally, the teeth of Lirainosaurus are different from those of the Late Cretaceous European titanosaurs described to date and also differ from the teeth of basal titanosauriforms from the Early Cretaceous of the Iberian Peninsula.     

Dental remains of Equatorius africanus from Kipsaramon, Tugen Hills, Baringo District, Kenya.

Forty-one isolated large hominoid teeth, as well as most of the mandibular and three maxillary teeth associated with a partial skeleton, were recovered from middle Miocene Muruyur sediments near Kipsaramon in the Tugen Hills, Baringo District, Kenya. The isolated teeth were collected as surface finds and the skeleton was excavated in situ at locality BPRP#122 dated between 15.58 Ma and 15.36 Ma. The majority of the teeth recovered at BPRP#122 are referable to a minimum of five individuals of the hominoid Equatorius africanus. Three of the teeth, however, are provisionally assigned to Nyanzapithecus sp. The new hominoids from Kipsaramon add to an increasing inventory of specimens that suggest greater large hominoid taxonomic diversity from the middle Miocene of Kenya than was previously recognized. It is suggested that there are two large-bodied hominoid species present at Mabako, only one of which is assignable to Equatorius.     

<Emphasis Type="Italic">Arkharavia heterocoelica</Emphasis> gen. et sp. nov., a new sauropod dinosaur from the Upper Cretaceous of the Far East of Russia

A new sauropod dinosaur, Arkharavia heterocoelica gen. et sp. nov., from the Maastrichtian (Udurchukan Formation) of the Amur Region, Russia, is described based on a tooth and several isolated anterior caudal vertebrae. It is distinguished by the saddle-shaped centrum and high neural spine of the anterior caudal vertebrae. Certain structural characters of the new genus are in common with Chubutisaurus insignis (Titanosauriformes) from the Upper Cretaceous of Argentina.     

Sauropod dinosaurs from the Lower Cretaceous of eastern Asia: taxonomic and biogeographical implications

Sauropod dinosaurs are poorly represented in the Lower Cretaceous of eastern Asia. Here, we describe a number of isolated sauropod teeth from the Kuwajima Formation (?Berriasian–?Hauterivian) of Shiramine, Japan. The mosaic of shared derived characters and symplesiomorphies displayed by the teeth indicate that they are referable to a basal member of the titanosauriform radiation. A taxonomic review of previously described sauropod specimens from eastern and south–eastern Asia reveals that a diversity of sauropods (including a titanosaurian, a basal titanosauriform and a ?euhelopodid, as well as several forms of indeterminate systematic position) was present in this region in the Early Cretaceous. This diversity conflicts with previous suggestions that eastern Asia was biogeographically isolated from the rest of Laurasia until the late Early Cretaceous and that the sauropod fauna was limited to the endemic East Asian clade Euhelopodidae. The presence of titanosauriform sauropods in the basal Cretaceous of Japan and Thailand indicate that the proposed faunal isolation of eastern Asia ended approximately 20 myr earlier than usually suggested.     

Nearly circular,oval and irregular holes in Cretaceous ammonoids from Nigeria

Nearly circular‐, oval‐ and irregular‐shaped holes are present in a collection of Late Cretaceous ammonoid cephalopods from southern Nigeria. Two competing hypotheses have been advanced to explain these holes: one is they were produced by diagenetic crushing of limpet home scars and the other is that they are predator's teeth marks. The latter explanation appears to be the best explanation for some of the damage seen in the Nigerian specimens. The suspected predator for some of the specimens was probably an unidentified reptile based on the diameters of the holes. Insofar as we are aware, this is the first recorded predatory damage reported on Cretaceous ammonoids from West‐Central Africa.